Fluid seal for freezing chamber openings



Jan. 24, 1967 M. Y. DREKSLER ET AL FLUID SEAL FOR FREEZING CHAMBEROPENINGS Filed April l, 1965 5 Sheets-Sheet l INVENTORS MOSHE Y.DREKSLER THOMAS F. SLOAN ATTORNEY g Jan. 24, 1967 M, Y, DREKSLER ET AL3,299,659

FLUID SEAL FOR FBEEZING CHAMBER OPENINGS 5 Sheets-Sheet 2 Filed April 1,1965 MOSHE Y. DREKSLER THOMAS F. SLOAN ,V /w/ /H/ ATTORNEY Jan. 24, 1967M. Y. DREKsLER ET AL 3,299,659

FLUID SEAL FOR FREEZING CHAMBER OPENINGS 3 Sheets-Sheet 5 Filed April 1,1965 INVENIORS MOSHE Y. DQEKSLER THOMAS F SLOAN ATTORNEY United StatesPatent O 3,299,659 FLUID SEAL FOR FREEZING CHAMBER OPENINGS Moshe Y.Dreksler, Waynesboro, and Thomas F. Sloan,

Znllinger, Pa., assignors to Frick Company, Waynesboro, Pa., acorporation of Pennsylvania Filed Apr. 1, 1965, Ser. No. 444,712 8Claims. (Cl. 62-266) The present invention relates to fluid means andmore particularly means for sealing openings in a freezing chamberthrough which material is carried into and from the chamber by aconveyor.

In freezing chambers having openings through which material is carriedby a conveyor into or from the chamber, it has been found necessary toenclose or seal the openings from the ambient atmosphere surrounding thechamber to reduce the rate of accumulation of frost on the evaporatorcoils or other heat exchange surfaces of the refrigerating system. Theproblem of reducing frost accumulation on the evaporator coil-s is aparticularly vexing problem when the freezing chamber is provided withopenings disposed one above the other. In such installations, the coldair passes from the lower opening into the ambient atmosphere because ofthe differential in pressure existing by virtue of the dense cold, airinside the chamber and the less dense, warm lair outside the chamber.The cold air passing from the inside of the chamber is replaced by warm,moist ambient air entering the upper opening. This situation creates acontinuous circulation and loss of cold air from the chamber and entryof warm moist air into the chamber which may be characterized as areverse chimney effect. Since the warm, ambient air is laden withmoisture which rapidly solidifes in the chamber in the form of frost onthe interior surfaces of the chamber and, particularly, on the surfacesof the evaporator tube bank, the installation has a relatively shortoperative life before shutdown of the unit for defrosting.

To solve the problem, various types of flexible mechanical seals havebeen devised, but none is capable of providing an effective enough sealto prevent passage of air through the opening through a wide range ofshapes and sizes of material transported by the conveyor.

It also has been sought to solve the aforementioned problem by inclosingat least the upper openings with insulated vwalls to form an anteroom orchamber adjacent the openings in which chamber dehumidifying devices areinstalled so that a relatively dry air enters the freezing chamberthrough the upper opening. While this apparatus solves the problem ofrapid frost accumulation within the freezing chamber, it is an expensivesolution to the problem. Also, if a similar anteroom is not providedadjacent the lower opening, cold air is lost through that opening, thusreducing the efficiency of the installation.

Accordingly, it is an object of this invention to provide a relativelyinexpensive and effective means for sealing the openings of a freezingchamber against the passage of air through those openings.

It is another object of this invention to provide a sealing meansadjacent at least the lowermost of two openings in a freezing chamber toprevent air circulation through the freezing chamber in the nature of areverse chimney effect.

A further object of the present invention is to provide a fluid sealingmeans adjacent an opening in a freezing chamber cooperatively associatedwith a mechanical sealing means to effectively prevent the passage ofair from the chamber.

It is, therefore, contemplated by this invention to provide a seal forthe openings of a freezing chamber, which openings have a conveyorextending therein transporting material through the openings, comprisinga mechanical sealing means disposed in the openings cooperativelyassociated with a uid means for discharging a continuous stream ofgaseous fluid, such as air, across the entire opening so as to impingethe conveyor and the material carried on the conveyor to thereby providea static pressure substantially equal to the air pressure within thefreezing chamber. The mechanical seal means, according to thisinvention, comprises a plurality of spaced, flexible walls whichresiliently engage the conveyor and the material transported by'theconveyor. The novel fluid seal means comprises a blower having anelongated, relatively narrow discharge outlet for emitting air in frontof and across the entire opening and against the conveyor and/or thematerial carried on the conveyor.

The invention will be more fully understood from the following detaileddescription thereof when considered in connection with the accompanyingdrawings in which:

FIG. 1 is an elevational view of a freezing chamber having two openingstherein and with the conveyor omitted for illustrative purposes;

FIG. 2 is a view in section taken substantially along line 2 2 of FIG.l;

FIG. 3 is a fragmentary View in section and on an enlarged scale of oneof the openings of the freezing chamber shown in FIGS. l and 2;

FIG. 4 is a fragmentary sectional view taken along line 4--4 of FIG. 3with a portion of the blower assembly broken away;

FIG. 5 is a sectional view taken substantially along line 5-5 of F IG.4;

FIG. 6 is a fragmentary view in section showing the inlet central meansof the blower assembly; and

FIG. 7 is an exploded view in perspective of the exible wall means ofthe mechanical seal assembly according to this invention.

Now referring to the drawings and more particularly to FIG. 1, 10generally designates a freezing chamber installation formed bycontiguous, heat insulated walls, including a roof 12 and an end wall14. The interior 16 of the freezing chamber installation 10 has anevaporation coil (not shown) which may comprise a bank of finned tubesdisposed within the freezing chamber and connected to the other suitablerefrigerating components of a refrigerating system disposed within oroutside of interior 16 of the freezing chamber installation 10. Anaccess port controlled by a door 18 is disposed in end wall 14 to enablean operator to gain access to interior 16 for purposes of inspectionand/or repair. Also, in wall 14 is provided two openings 20 and 22, oneof which is for the entry `of material to be frozen while the otheropening provides for removal of the frozen material.

As best shown in FIG. 3, each opening is lined or framed by arectangular shaped duct 24, which comprises a top 26, a bottom 28 andopposite side walls 30 and 32. Partially extending into each duct 24 arethe ends of two conveyor assemblies 34 and 36, each of which comprisesan endless conveyor in the form of a foraminous belt 38 and 40, rollers42 and 44, respectively, and a suitable belt driving means (not shown).The material, such as package 46, is carried on the upper course of eachof the foraminous belts 38 and 40 through the duct 24. Each of the ducts24 may be positioned and secured within the respective openings 20 and22 by means of flanges 48 projecting from the top 26 and bottom 28 ofthe duct and spaced to engage opposite sides of wall 14 adjacent theperiphery of the openings. i

A mechanical sealing assembly is disposed within duet 24, which assemblycomprises a plurality of flexible walls 50 extending across the width ofeach belt 38 and 40 and spaced from each other along the longitudinalaxis of the belts to form air locks or chambers therebetween. Thespacing of the walls 50 is determined upon the size of the materialconveyed, such as a package 46, and the predetermined loading of theconveyor belt so that at least one wall 50 throughout its length is inengagement with a conveyor. Each wall 50 is secured to the inner surfaceof the top wall 26 of duct 24. As best shown in FIG.` 7, each wall 50comprises a pair of flexible members or sheets 52, each of which isprovided with a plurality of spaced slits extending from one end edgethereof to a point spaced from the opposite end edge to form a pluralityof resilient fingers 54. The flexible sheets 52 are held in side-by-siderelationship to each other by a U-shaped frame 56 in such manner thatthe slits of one flexible sheet are laterally offset from the slits ofthe other flexible sheet so that a finger of one flexible sheet overlapsthe slit between adjacent fingers 54 of the other flexible sheet. Theframe 56 is secured, as by welding or in some other suitable manner, tothe inner surface of top wall 26 of duct 24 so that the distal end offingers 54 engage the conveyor belts 38 and 40. The mechanical seal alsoincludes flexible sealing members 58 which are secured to the innersurface of bottom wall 28 of duct 24 and project upwardly so that thedistal ends of members 5S engage the return course of belts 38 and 40.The flexible sealing members 58 are required to prevent the flow of airfrom interior 16 as will be more fully explained hereinafter. To furtherseal the openings, each mechanical sealing assembly may include asealing wall 60 supported by end walls 30 and 32 of duct 24 between thesupply and return course of belt 40. Flexible strips 62 are securedalong the upper and lower edges of wall 60 to engage belt 40.

To support packages 46 while being transferred from one conveyor 34 or36 to the other, a plurality of support rods 64 are disposed to extendacross duct 24 in the space between conveyors.

In addition to the mechanical sealing assembly, the

The blower 66 is arranged and adjusted to provide a stream of .air whichupon impingement `against conveyor belt 40 and/ or packages 46 creates afluid static pressure across the flow area of duct 24 which issubstantially equal to the air pressure within freezing chamber 10adjacent the associated duct 24. To provide this desired static pressurebelow the return course of conveyor belt 40, bottom wall 28 of duct 24is extended at 28A to pro'- vide a surface against which the air passingthrough the lower or return course of the conveyor belt can impinge.

The flexible sealing members 58 of the mechanical sealing assemblyfunctions to minimize air leakage in the areas across the width of duct24 which from time to time does not have the benefit of the static fluidpressure -seal because of packages which block flow of air` the conveyorbelt.

While the apparatus is shown with the ends of two conveyors 34 and 36projecting into duct 24, it is to be understood that the invention isapplicable to a` structure wherein a single conveyor extends into andthrough duct 24 without departure from the scope and spirit of thisinvention. In addition, while the fluid seal and mechanical sealaccording to this invention have been shown and described for the loweropening in freezing chamber 10, it is within the purview of the presentinvention to provide af-lblower 66 adjacent the upper opening within thefreezing chamber, as shown in broken lines in FIGS. 1 and 2, andcooperatively associated with the novel mechanical seal assembly similarto that described for the lower opening. This blower 66 provides astatic pressure withinA the freezing chamber to prevent ambient air frombeing sucked through the opening into the chamber.

Although but one embodiment of the invention has been illustrated anddescribed in detail, it s to be expressz in the art.

present invention includes an air blower 66 arranged to i cooperate withthe flexible walls 50 and 58 of the mechanical sealing assembly and belt40 to reduce air leakage through duct 24 to a negligible amount over awide variety of shapes and sizes of material being conveyed through theducts and a wide range of load on the conveyors.

As best shown in FIGS. 3, 4, 5 and 6, the blower 66 comprises a housing68 in which Ia motor 70 is mounted to drive two impellers or fans '72mounted on the rotor of the motor. Each of the fans 72 is disposedadjacent a screened inlet port 74 in the opposite end walls of housing68 to draw ambient air into the housing and discharge the same throughan elongated, discharge port 76 in the bottom of housing 68. The entireblower assembly is secured to wall 14 of freezing chamber l@ by means ofa plurality of spaced mounting bolts 78 so that the discharge port 76 inhousing 68 is disposed above and adjacent duct 24. The discharge port 76may be provided with guide vanes 80 to distribute and direct the airdischarge downwardly and substantially normal to conveyor belt 40. Thecapacity of blower 66 may be regulated by angular adjustment of theslotted discs 82 relative to each other, which discs are mounted in eachinlet port 72.

Since the construction of the blower forms no part of the invention, anyblower capable of discharging a continuous stream of air across theentire width of Aconveyor belt 40 and substantially normal to the latterwill be applicable t-o the present invention without departing from thescope and spirit of the present invention. One such blower applicable tothis invention is disclosed in the U.S. patent to Morrison, No.3,145,641.

What is claimed is:

1. In a freezing chamber defined by wall means having at least oneopening in said wall means communicating the chamber with the ambientatmosphere' and having a foraminous conveyor. extending into saidopening to transport material through the opening; the combination of amechanical seal means comprising, a plurality of spaced flexible ,wallsdisposed within the opening and engaging the conveyor and said materialtransported by the conveyorto provide atleast a partial sealing of-theopening, and a fluid seal means comprising blowermeans for discharging astream of gaseous fluid across said opening so as to impinge saidconveyor and the material on said conveyor andthereby create a staticfluid pressure adjacent said opening to prevent passage of air throughthe opening, and a baille means disposed adjacent said opening on theside of the foraminous conveyor opposite from the blower lmeans andprojecting from the chamber wall means so that the fluid stream passingthrough the foraminous conveyor impinges thereon to create a fluidstatic pressure adjacent the opening on the side of the conveyoropposite from the blower means.

2. In a freezing chamber having at least one opening disposed in one ofthe walls defining the freezing chamber and a foraminous conveyorextending through the opening for transporting material through theopening, the combination of a mechanical seal means comprising aplurality of spaced flexible walls disposed within each of the openingsand engaging the conveyor and the material carried on the conveyor toprovide at least a partial seal as the material is transported throughthe opening, a blower disposed adjacent the opening and exteriorly ofthe wall to discharge a continuous stream of air across the opening andin impingement against the conveyor and the material carried on theconveyor to thereby-provide a static pressure adjacent the opening abovethe belt substantially equal to the pressure in the freezing chamberadjacent the opening and prevent the passage of air from inside thechamber to the ambient atmosphere through the opening, and meansdisposed below said conveyor and in the path of the air stream againstwhich the latter impinges to provide a static pressure across theopening and below the conveyor substantially equal to the pressure ofthe air within the freezing chamber adjacent said open- 3. Thelapparatusof claim 2 wherein each of the llexible walls comprises two rows of aplurality of adjacent fingers with the fingers in one row offset fromthe ngers of the other rowso that one row of fingers covers the spacebetween the fingers of the other row.

4. Therapparatus of claim 2 wherein said blower has an elongated,relatively narrow air discharge outlet.

5. The apparatus of claim 2 wherein said impinging means comprises aprojecting member which forms part of a lining of the opening in thefreezing chamber wall.

6. A mechanical seal assembly for an opening in a wall of a plurality ofwalls forming a chamber and through which opening an endless foraminousconveyor belt means extends to carry material through the opening, saidassembly comprising a plurality of spaced first flexible walls dependingfrom the top wall of the opening and engaging at their distal ends thetop of the conveyor means, a plurality of spaced second flexible wallsprojecting from the bottom wall of said opening and engaging at thedistal ends thereof the underside of said conveyor means, each of saidfirst walls comprising a plurality of adjacent ilexible sheets, each ofthe flexible sheets having a plurality of parallel slits to form fingerscapable of independent ilexure, each of the ilexible sheets beingdisposed in abutting s ide by side relationship with the lingers of onesheet offset from the fingers of the next adjacent sheet.

7. In a freezing chamber having at least one opening in a wall definingsaid chamber and a foraminous conveyor extending into said opening totransport material through the opening, a sealing means for said openingcomprising a fluid seal means secured to said wall for discharging astream of gaseous tluid across said opening so as to impinge saidconveyor and the material on said conveyor and thereby create a staticfluid pressure adjacent said opening, and a baille means adjacent saidopening on the side of the conveyor opposite from the fluid seal meansand projecting from said chamber wall so that the gaseous fluid streampassing through the conveyor impinges thereon to create a fluid staticpressure adjacent the opening on the side of said conveyor opposite fromthe fluid seal means.

8. A mechanical fluid seal assembly for an opening in a wall of aplurality of walls defining a chamber and through which opening aconveyor means extends to carry material through the opening, saidassembly comprising a plurality of spaced first flexible walls dependingfrom the top wall of the opening and engaging at their distal ends thetop of the conveyor means and a plurality of spaced second ilexiblewalls projecting from the bottom wall of said opening to engage theunderside of the conveyor means, each of said first and second ilexiblewalls comprising a flexible sheet having a plurality of spaced slitsextending from the distal end to a point in spaced relationship with theopposite end to thereby form a plurality of llexible fingers, and eachof said irst walls comprises a plurality of ilexible sheets, each of theflexible sheets being provided with a plurality of spaced sheetsextending from the distal end thereof to a point spaced from theopposite end to thereby form ya plurality of flexible ngers, each ofsaid plurality of flexible sheets being disposed side by side with thefingers of one sheet being offset from the fingers of the next adjacentsheet.

References Cited by the Examiner UNITED STATES PATENTS 1,361,977 12/1920Fuller 263-50 2,300,229 10/1942 Knowles 62-380 X 2,620,573 12/1952McMahon 34-242 X 3,114,248 12/1963 Morrison 62`380 X 3,200,776 8/1965Simpson 263-50 X 3,255,608 6/1966 Macintosh 62-380 X ROBERT A. OLEARY,Primary Examiner.

MEYER PERLIN, Examiner.

W. E. WAYNER, Assistant Examiner.

1. IN A FREEZING CHAMBER DEFINED BY WALL MEANS HAVING AT LEAST ONEOPENING IN SAID WALL MEANS COMMUNICATING THE CHAMBER WITH THE AMBIENTATMOSPHERE AND HAVING A FORAMINOUS CONVEYOR EXTENDING INTO SAID OPENINGTO TRANSPORT MATERIAL THROUGH THE OPENING; THE COMBINATION OF AMECHANICAL SEAL MEANS COMPRISING, A PLURALITY OF SPACED FLEXIBLE WALLSDISPOSED WITHIN THE OPENING AND ENGAGING THE CONVEYOR AND SAID MATERIALTRANSPORTED BY THE CONVEYOR TO PROVIDE AT LEAST A PARTIAL SEALING OF THEOPENING, AND A FLUID SEAL MEANS COMPRISING BLOWER MEANS FOR DISCHARGINGA STREAM OF GASEOUS FLUID ACROSS SAID OPENING SO AS TO IMPINGE SAIDCONVEYOR AND THE MATERIAL ON SAID CONVEYOR AND THEREBY CREATE A STATICFLUID PRESSURE ADJACENT SAID OPENING TO PREVENT PASSAGE OF AIR THROUGHTHE OPENING, AND A BAFFLE MEANS DISPOSED ADJACENT SAID OPENING ON THESIDE OF THE FORAMINOUS CONVEYOR OPPOSITE FROM THE BLOWER MEANS ANDPROJECTING FROM THE CHAMBER WALL MEANS SO THAT THE FLUID STREAM PASSINGTHROUGH THE FORAMINOUS CONVEYOR IMPINGES THEREON TO CREATE A FLUIDSTATIC PRESSURE ADJACENT THE OPENING ON THE SIDE OF THE CONVEYOROPPOSITE FROM THE BLOWER MEANS.